Aix, when spring time comes, and the water will allow, young will move. Some go up, some go down. It continues that way and will get as crowded as the waterways will hold. If there's not enough water, they'll find a way to make more.
There are a few rules I try to live by after having educated my share.
1. No matter how much my mouth watered on setting that perfect spot that you KNOW a beaver will travel through.....it may not be the best thing to do. Yet. Sometimes it's impossible, but I want zero beaver to know what's going on until the sheer drop in numbers is the only thing raising a red flag.
I don't mind setting hard, but only if I can hide my catch underwater. At first.
Sometimes I know my approach will be slower up front but it pays off in the back end.
I'll drop a trap at every castor mound and crossover where I can drown and I won’t use even a drop of lure. If there's a long string of dams, I like to work the lower end first. Footholds are key here. You can put a bodygrip on a drowner for hiding purposes but it doesn't always work out.
Once I wear them out, I'll use 330s at the lower ends and maybe a dab of lure on the mounds as I go. I rarely pull a trap unless I have to.
Move on up closer to their fort and hit them the same way as above. In the end I like to use a little lure but will also make food lured sets depending on the circumstances.
It's really not possible to lay out a specific approach. There are times where there are ZERO existing castor mounds and I personally wouldn't introduce any. They're absent for a reason.
Once I'm to that point, I'll start breaking lower dams. I try not to change the environment or water levels on purpose at first. That's not to say I never have, because thousands of beaver bit the dust that way. I just approach situations like yours as if I know there are 20 beaver present and I only have 1 shot to get it right or the job just got extended by a week or a month or two.
Once the dams are broken, and there's no more takers to repair, plug the channels with 330s. That'll be the deepest water for travel. And I'll leave traps several days with no action. Sometimes a beaver will hole up for several days. Ill plug a 330 in the den entrance if I know I'm down that far.
I hope my thoughts and spelling were coherent. It's 0430. Lol.